Carbide drop out?

[kcbladez]

Has anyone heard of carbide drop-out appearing as acid corrosion-like damage on the blade??

 

[mete]

It's possible to corrode the steel matrix but not the carbides though I don't remember hearing such a thing on knives. When there are two of more phases to a metal it's possible and I've seen it in metals .I've seen 'dezincification" and 'denickelization' where the zinc rich and nickel rich phase has corroded away !! It seems that a galvanic type corrosion is set up between the two phases. A friend of mine had seen a ships hatch of aluminum where one phase had corroded away but to the eye it looked OK but he could actually flex the hatch !!